Aircraft turbojet engine nacelle, propulsion unit and aircraft including such a nacelle

Abstract

An aircraft turbojet engine nacelle includes a rear section without a lower bifurcation, the rear section including a thrust reverser system, and the thrust reverser system including a movable cowl. The nacelle includes a guide system including a movable portion and a fixed portion, the movable portion being secured in translation to the movable cowl and cooperating with the fixed portion and the fixed portion being fixed relative to the nacelle. The guide system is disposed proximate to a position called the “6 O'clock” position. In one form, the length of the fixed portion of the guide system is larger than or equal to 50% of the length of the movable portion.

Claims

1. An aircraft turbojet engine nacelle comprising: a rear section without a lower bifurcation, the rear section including a thrust reverser system having a movable cowl; and a guide system including a movable portion and a fixed portion, the movable portion being secured in translation to the movable cowl and cooperating with the fixed portion, the fixed portion being fixed relative to the nacelle, the guide system being disposed at a 6 O'clock position, wherein the thrust reverser system includes thrust reverser cascades, the movable portion being disposed between adjacent two of the thrust reverser cascades and defining a cavity for receiving the fixed portion, the fixed portion being disposed on an inner side of the movable portion, wherein a length of the fixed portion of the guide system is larger than or equal to 50% of a length of the movable portion, and wherein, in a retracted position of the movable cowl, the length of the fixed portion is engaged between the adjacent two of the thrust reverser cascades, and in a deployed position of the movable cowl, a rear fastening end of the fixed portion is disposed upstream from said adjacent two of the thrust reverser cascades.

2. The nacelle according to claim 1, wherein the length of the fixed portion of the guide system is larger than or equal to 80% of the length of the movable portion.

3. The nacelle according to claim 1, wherein the fixed portion forms a rail cooperating with the movable portion, the movable portion forming a guideway and including the cavity adapted to receive the fixed portion.

4. The nacelle according to claim 1, wherein the fixed portion is secured to a peripheral frame fastened to a fan casing of a turbojet engine, or directly fastened to the fan casing.

5. The nacelle according to claim 4, wherein the fixed portion includes at least two fastening points.

6. The nacelle according to claim 1, wherein the thrust reverser cascades are sliding-type, and a front end of the movable portion is secured to a front peripheral frame secured to the thrust reverser cascades.

7. The nacelle according to claim 1, wherein a rear end of the movable portion is secured to a peripheral frame of the movable cowl.

8. An aircraft propulsion unit including a bypass turbojet engine, the aircraft propulsion unit comprising a nacelle according to claim 1.

9. The aircraft propulsion unit according to claim 8, wherein the fixed portion of the guide system is fastened to a fan casing.

10. An aircraft including at least one aircraft propulsion unit according to claim 8, the at least one aircraft propulsion unit being supported by a mast, the aircraft including guide rails for guiding the movable cowl of the nacelle, the guide rails being fastened on the mast or on a structure secured to at least one of the mast and the turbojet engine.

11. The nacelle according to claim 1, further comprising a front peripheral frame and an intermediate casing shell disposed downstream from the front peripheral frame, wherein the fixed portion is secured to the intermediate casing shell and the movable portion is secured to the front peripheral frame.

12. The nacelle according to claim 11, wherein the fixed portion has a front fastening portion secured to a fan casing and a rear fastening portion secured to the intermediate casing shell, and the movable portion has a front end secured to the front peripheral frame.

13. The aircraft turbojet engine nacelle according to claim 1, wherein the fixed portion includes a front fastening end fastened to a fan casing and the rear fastening end fastened to an intermediate casing shell disposed downstream from the fan casing.

14. The aircraft turbojet engine nacelle according to claim 13, wherein: the thrust reverser cascades have front ends fixed to a front peripheral frame; in the retracted position of the movable cowl, the front fastening end of the fixed portion is disposed proximate the front peripheral frame; and in the deployed position of the movable cowl, the rear fastening end of the fixed portion is disposed proximate the front peripheral frame.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1a represents a nacelle in a “direct jet” configuration according to the present disclosure;

(3) FIG. 1b represents a nacelle in a “reverse jet” configuration according to the present disclosure;

(4) FIG. 2a is a partial view of the rear section of the nacelle of FIGS. 1a and 1b with the thrust reverser system in the retracted position;

(5) FIG. 2b is a partial view of the rear section of the nacelle of FIGS. 1a and 1b with the thrust reverser system in the deployed position;

(6) FIG. 3a is a detailed view of FIG. 2a;

(7) FIG. 3b is a detailed view of FIG. 2b;

(8) FIG. 4a is a partial view of the nacelle of FIGS. 1a and 1b with the thrust reverser system in the retracted position;

(9) FIG. 4b is a partial view of the nacelle of FIGS. 1a and 1b with the thrust reverser system in the deployed position; and

(10) FIG. 5 represents a partial view of a turbojet engine in accordance with the present disclosure, showing one form of the fixed portion of the guide system, said fixed portion being fastened on the fan casing of the turbojet engine.

(11) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(12) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(13) FIGS. 1a and 1b show a view of a nacelle 1 in accordance with the present disclosure. This conventionally includes an air inlet 2, a middle section 3, as well as a rear section 4. In FIG. 1a, the nacelle 1 is represented alone, while in FIG. 1b, there is shown the nacelle 1 mounted on a mast 5 (also known as “reactor strut” or a pylon). Moreover, FIG. 1a shows the nacelle in the “direct jet” configuration, that is to say with the thrust reverser system in the retracted position, whereas FIG. 1b shows the nacelle in the “reverse jet” configuration, that is to say with the thrust reverser system in the deployed position. Thus, it is shown in FIG. 1b that a movable cowl 20 of the rear section 4 is in the retracted position, revealing a set of thrust reverser cascades 22. In the example, the movement of the movable cowl 20 is supported and guided by rails 50 disposed on either side of the mast 5.

(14) In the example, the structure of the nacelle is of an “O-duct” type and therefore does not include a bifurcation (or connection island) in the lower portion of the cold flow path. It should be noted that the present disclosure is also applicable to a nacelle with a c-shaped structure.

(15) FIGS. 2a and 2b represent a portion of the rear section of the nacelle of FIGS. 1a and 1b, showing in particular the components of the thrust reverser system, respectively in the retracted position and in the deployed position.

(16) The thrust reverser system comprises a movable cowl 20, in the example in one-piece, which forms the external surface of the rear section of the nacelle. The movable cowl 20 is slidably mounted, in the example via the rails 50, secured to the mast 5 supporting the propulsion unit (namely the assembly formed by a turbojet engine and the associated nacelle). The thrust reverser system further comprises thrust reverser cascades 22, in the example sliding cascades, and blocking flaps 24 movable in rotation. The thrust reverser system includes actuators 25, in particular electromechanical actuators, allowing making the movable cowl slide between its retracted position (FIG. 2a) and its deployed position (FIG. 2b), and vice versa.

(17) When the thrust reverser system is retracted (FIG. 2a):

(18) the movable cowl 20 is in the retracted position, corresponding to a forward position in which it provides the aerodynamic continuity with the middle section of the nacelle;

(19) the blocking flaps 24 are in the retracted position, a position in which they do not obstruct the cold flow path; and

(20) the thrust reverser cascades 22 are in the retracted (or forward) position, a position in which they are disposed around the fan casing of the turbojet engine.

(21) When the thrust reverser system is deployed (FIG. 2b):

(22) the movable cowl is in the deployed position, corresponding to a rearward position, in which it uncovers the thrust reverser cascades 22 which are in their rearward position;

(23) the blocking flaps 24 are in the deployed position, a position in which they at least partially obstruct the cold flow path; and

(24) the thrust reverser cascades 22 are in the deployed (or rearward) position, a position in which they are disposed at the rear of the fan casing of the turbojet engine, and in which they redirect the cold flow outwardly and forwardly of the nacelle.

(25) It should be noted that, in the example, the thrust reverser cascades 22 includes sliding cascades, these being linked in translation to the movable cowl 20, and the relative position of the thrust reverser cascades 22 relative to the movable cowl 20 does not vary during the deployment or the retraction of the thrust reverser system.

(26) The thrust reverser cascades 22 are secured to a front peripheral frame 26. Several housings 28 are provided for the actuators of the thrust reverser system. These housings 28, four in the example of the figures, are disposed between some of the thrust reverser cascades 22.

(27) In the “six O'clock” position (or proximate to this position), a guide system is disposed, including a movable portion 30, secured in translation to the movable cowl 20, and a fixed portion 32, secured to a fixed portion of the nacelle and/or secured to the turbojet engine associated to the nacelle.

(28) Advantageously, the movable portion 30 is disposed at the location normally occupied by a cascade called solid cascade (generally known as “blank off”), such a solid cascade being provided to inhibit a redirection of the cold flow downwards. Thus, the movable portion 30 of the guide system is advantageously disposed between two thrust reverser cascades 22, at the rear of the front peripheral frame 26 of the cascades 22.

(29) In accordance with the present disclosure, the movable portion 30 of the guide system is fixed relative to the movable cowl 20 (and therefore, in the example, relative to the thrust reverser cascades 22), being in the example fastened to the front peripheral frame 26. The movable portion 30 forms a guideway cooperating with the fixed portion 32 which forms a guide rail. The fixed portion 32 of the guide system is fixed relative to the non-movable elements of the nacelle and the propulsion unit. In the example, the fixed portion 32 is intended to be fastened to the fan casing of the turbojet engine associated to the nacelle. As shown in FIGS. 2a and 2b, the relative position of the fixed 32 and movable 30 portions of the guide system is related to the position of the movable cowl 20 and therefore of the thrust reverser cascades 22. This relative position has two extremes, corresponding to the retracted and deployed positions of the thrust reverser system. These two extreme positions are better shown in FIGS. 3a, 4a (retracted thrust reverser) and 3b, 4b (deployed thrust reverser). These figures show that, in accordance with the present disclosure, the length of the fixed portion 32 (or rail) engaged (in the forward position of the movable cowl 20) in the movable portion is larger than or equal to 50% (and in other forms, larger than or equal to 60% or larger than or equal to 80%) of the length of the movable portion 30 (or guideway), thus allowing a long type guidance. In the example, the length of the fixed portion 32 is equal to (or close to) the length of the movable portion 30. Advantageously, the length of the movable portion 30 is larger than the stroke of the movable cowl. Thus, when the movable cowl is in the rearward position, a portion of the fixed portion remains engaged in the movable portion. In this case, it will advantageously be possible to limit the length of the portion remaining engaged in the rearward position of the movable cowl, this being for example smaller than or equal to 20% of the length of the movable portion. Thus, the advantages of a “short” guidance, when the movable cowl is in the rearward position (reverse jet position), will be combined with the advantages of a “long” guidance when the movable cowl is in the forward position (direct jet position).

(30) As shown in particular in FIGS. 3a, 3b, and 4a, 4b, the movable portion 30 of the guide system includes a body 300 which has a front portion 302, provided to be fastened to the front peripheral frame 26, for example by splicing, and a rear portion 304, provided to be fastened to the movable cowl 20, for example by riveting and/or splicing. In the example, the movable portion 30 is secured to a peripheral frame 202 of the movable cowl 20. The guide system 30 includes a longitudinal cavity shaped to receive the fixed portion 32.

(31) FIG. 5 shows an example of fastening the fixed portion 32 on a turbojet engine fan casing 320, the assembly being viewed from the side. In the example, the fixed portion 32 includes two remote fastening portions. The first fastening portion, or front fastening portion 322, allows fastening the fixed portion 32 directly to the fan casing 320, more specifically to a fastening flange of the fan casing. The second fastening portion, or rear fastening portion 324, allows fastening the fixed portion 32 to the intermediate casing shell 34, itself fastened to the fan casing 320. Advantageously, the rear fastening portion 324 will be integrally made in one-piece with the fixed portion 32, whereas the front fastening portion 322 will be attached.

(32) In a variant which is not represented, the movable portion of the guide system could have, at the level of its rear portion, an extension extending in the form of a beam secured to the movable cowl 20. Thus, via this extension, the movable portion of the guide system will be securely fastened to the movable cowl 20 and will participate in the rigidity thereof.

(33) In a variant which is not represented, it may be provided that it is the movable portion of the guide system which forms a guide rail whereas the fixed portion 32 forms a guideway cooperating with the guide rail.

(34) Although the present disclosure has been described with reference to a particular form, it is obvious that it is not limited thereto and that it comprises all technical equivalents of the described means as well as the combinations thereof.

(35) Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, manufacturing technology, and testing capability.

(36) As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

(37) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.